1. Field of the Invention
The present invention relates to a deflecting/scanning apparatus having an air bearing and serving to scan a light beam such as a laser beam on a photosensitive member.
2. Related Background Art
A bearing rotating apparatus using an air bearing in a conventional deflecting/scanning apparatus is disclosed in, e.g., Japanese Laid-Open Patent Application No. 6-75185. As shown in FIG. 1, this apparatus comprises a motor housing 1, a stationary shaft 2 held by the motor housing 1, and a rotating sleeve 3. A rotating polygon mirror 5 is fixed to the rotating sleeve 3 with a leaf spring 6 via a rotating member 4. The rotating member 4 has a drive magnet 7. A drive motor 10 for rotating the rotating sleeve 3 is constituted by the drive, magnet 7, a stator 8, and a motor board 9 on which electric parts and the like are mounted.
In the above prior art, however, since the rotating sleeve 3 is not in the form of a bag with respect to the stationary shaft 2, no air damper effect can be obtained. This structure is therefore susceptible to vibrations in the thrust direction. Forming the rotating sleeve 3 into a bag-like shape costs too much because it is difficult to process a ceramic material. In addition, a vent hole is required to facilitate assembly of the rotating sleeve 3 and the stationary shaft 2. However, in order to obtain an air damper effect, the vent hole must be sealed after the assembly.